Nuclear Energy
Nuclear fission provides low-carbon electricity.
About this topic
Nuclear power stations use fission of uranium-235 to heat water into steam that drives turbines. A small amount of fuel gives enormous energy, with no CO₂ emissions during generation, providing reliable base-load power. Control rods absorb neutrons to regulate the chain reaction, and a moderator slows neutrons.
Concerns: radioactive waste that stays hazardous for thousands of years, the risk of accidents (Chernobyl, Fukushima), high construction costs and proliferation. Fusion research aims to provide cleaner nuclear energy in the future.
The physics is E = mc squared at work: splitting a uranium-235 nucleus after it absorbs a neutron releases about 200 MeV and two or three more neutrons, which can split further nuclei in a chain reaction. One kilogram of uranium-235 fully fissioned releases about as much energy as around 2,700 tonnes of coal, and a pellet the size of a fingertip is equal to about a tonne of coal. France gets about 70 percent of its electricity from nuclear plants and has low carbon emissions.
Reactors are designed with multiple safety layers: containment buildings, control rods of boron or cadmium, and cooling systems. Per unit of energy, nuclear has one of the lowest death rates and lifecycle emissions, comparable to wind. Waste is small in volume, and used fuel is stored in pools and dry casks, while deep geological repositories such as Finland's Onkalo are being built. Newer designs include small modular reactors. A common misconception is that a reactor can explode like a bomb; the fuel is not enriched enough. The real risk is overheating if cooling fails. Fission splits atoms, while fusion joins them, as in the Sun, and is still experimental.
Key ideas
- Uranium fuel
- Waste needs safe storage
- No CO₂ during operation
Quick check
Use cases: where Nuclear Energy helps
- Homework: review the key idea behind Nuclear Energy before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Nuclear Energy without notes.
- Visual learning: play with the interactive lab to see how Nuclear Energy changes when you adjust its inputs.
- Teaching a friend: explain Nuclear Energy in your own words, then compare your version with the key ideas.
Earth science helps with weather forecasts, natural hazards, energy and climate planning.
Frequently asked questions
What is Nuclear Energy?
Nuclear fission provides low-carbon electricity.
What will I learn in Nuclear Energy?
Uranium fuel. Waste needs safe storage. No CO₂ during operation.
Is Nuclear Energy part of Earth & Space?
Yes. It is one of 60 Earth & Space topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Nuclear Energy lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Nuclear Energy?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.